Tritium (T) is a hydrogen atom that has two neutrons in the nucleus and a single proton, giving it an atomic weight near three. Tritium has a half-life of 12.3 years and emits a very weak beta particle. Tritium replaces one of the stable hydrogens in the water molecule to form tritiated water. Apart of its natural formations in the upper atmosphere when cosmic rays strike nitrogen molecules in the air, tritium is produced during nuclear weapons explosions as a byproduct as well as in commercial reactors producing electricity and in special production reactors like in the government weapons production plants. Although tritium can be a gas, its most common form is in water which is formed when it reacts with oxygen to form tritiated (radioactive) water.
Tritiated water is concentrated in respect to tritium by isotopic separation. This allows the dispersion of a large quantity of very low activity water to the environment and the required fixation of a small quantity of relatively high activity tritiated water. It also allows the recovery of deuterium for tritiated heavy water wastes from certain types of fission reactors.
Tritium is considered one of the most innocuous of fission products. Tritiated water and its vapor can be taken into the body by skin penetration. The retention of tritium in the body is dependent on the chemical form in which it enters. The probability of genetic and somatic damage from tritium exposure is enhanced when tritium is ingested,
The most common documented sources of tritium in the environment are (a) from improper disposal of this isotope in municipal landfills, and (b) from leakages occurring from commercial reactors. If improperly stored, it seeps through landfills and passes into waterways, carrying the radioactive tritium with it.
As with all ionizing radiation, exposure of humans to tritium increases the risk of developing cancer. This is the reason why the Environmental Protection Agency (EPA) has established standards for the maximum amount of tritium that may be released by nuclear facilities or quantity that may be found in drinking water.
The present methods of eliminating tritiated water (water contaminated with radioactive tritium) involve compounds with liquids and solids or absorption of the contaminated water with organic molecules through non-covalent binding during storage. This method of elimination, by a “reversible” chemical entrapment represents a temporary solution to the problem of protecting the environment. Being reversibly bound, tritiated water would ultimately seep out of its usual underground storage and ultimately contaminate waterways.